let n, j be Nat; :: thesis: for F being FinSequence of the carrier of (RealVectSpace (Seg n))
for Bn being Subset of (RealVectSpace (Seg n))
for v0 being Element of (RealVectSpace (Seg n))
for l being Linear_Combination of Bn st F is one-to-one & Bn is R-orthogonal & rng F = Carrier l & v0 in Bn & j in dom (l (#) F) & v0 = F . j holds
(Euclid_scalar n) . v0,(Sum (l (#) F)) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0)

let F be FinSequence of the carrier of (RealVectSpace (Seg n)); :: thesis: for Bn being Subset of (RealVectSpace (Seg n))
for v0 being Element of (RealVectSpace (Seg n))
for l being Linear_Combination of Bn st F is one-to-one & Bn is R-orthogonal & rng F = Carrier l & v0 in Bn & j in dom (l (#) F) & v0 = F . j holds
(Euclid_scalar n) . v0,(Sum (l (#) F)) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0)

let Bn be Subset of (RealVectSpace (Seg n)); :: thesis: for v0 being Element of (RealVectSpace (Seg n))
for l being Linear_Combination of Bn st F is one-to-one & Bn is R-orthogonal & rng F = Carrier l & v0 in Bn & j in dom (l (#) F) & v0 = F . j holds
(Euclid_scalar n) . v0,(Sum (l (#) F)) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0)

let v0 be Element of (RealVectSpace (Seg n)); :: thesis: for l being Linear_Combination of Bn st F is one-to-one & Bn is R-orthogonal & rng F = Carrier l & v0 in Bn & j in dom (l (#) F) & v0 = F . j holds
(Euclid_scalar n) . v0,(Sum (l (#) F)) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0)

let l be Linear_Combination of Bn; :: thesis: ( F is one-to-one & Bn is R-orthogonal & rng F = Carrier l & v0 in Bn & j in dom (l (#) F) & v0 = F . j implies (Euclid_scalar n) . v0,(Sum (l (#) F)) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0) )
assume A1: ( F is one-to-one & Bn is R-orthogonal & rng F = Carrier l & v0 in Bn & j in dom (l (#) F) & v0 = F . j ) ; :: thesis: (Euclid_scalar n) . v0,(Sum (l (#) F)) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0)
A2: Carrier l c= Bn by RLVECT_2:def 8;
A3: dom (l (#) F) = Seg (len (l (#) F)) by FINSEQ_1:def 3;
reconsider rv0 = v0 as Element of REAL n by FINSEQ_2:111;
reconsider F2 = l (#) F as FinSequence of the carrier of (RealVectSpace (Seg n)) ;
consider f being Function of NAT ,the carrier of (RealVectSpace (Seg n)) such that
A4: ( Sum F2 = f . (len F2) & f . 0 = 0. (RealVectSpace (Seg n)) & ( for j2 being Element of NAT
for v being Element of (RealVectSpace (Seg n)) st j2 < len F2 & v = F2 . (j2 + 1) holds
f . (j2 + 1) = (f . j2) + v ) ) by RLVECT_1:def 13;
A5: ( len (l (#) F) = len F & ( for i being Element of NAT st i in dom (l (#) F) holds
(l (#) F) . i = (l . (F /. i)) * (F /. i) ) ) by RLVECT_2:def 9;
then A6: dom (l (#) F) = Seg (len F) by FINSEQ_1:def 3
.= dom F by FINSEQ_1:def 3 ;
A7: ( 1 <= j & j <= len F ) by A1, A3, A5, FINSEQ_1:3;
defpred S1[ Nat] means ( $1 < j implies (Euclid_scalar n) . v0,(f . $1) = 0 );
(Euclid_scalar n) . v0,(f . 0 ) = |(rv0,(0* n))| by A4, Th45
.= 0 by EUCLID_4:23 ;
then A8: S1[ 0 ] ;
A9: for k being Element of NAT st S1[k] holds
S1[k + 1]
proof
let k be Element of NAT ; :: thesis: ( S1[k] implies S1[k + 1] )
assume A10: S1[k] ; :: thesis: S1[k + 1]
now
per cases ( k < len F2 or k >= len F2 ) ;
case A11: k < len F2 ; :: thesis: verum
then A12: k + 1 <= len F2 by NAT_1:13;
1 <= k + 1 by NAT_1:11;
then k + 1 in Seg (len F2) by A12, FINSEQ_1:3;
then k + 1 in dom F2 by FINSEQ_1:def 3;
then F2 . (k + 1) in rng F2 by FUNCT_1:def 5;
then reconsider v = F2 . (k + 1) as Element of (RealVectSpace (Seg n)) ;
reconsider fk = f . k as Element of REAL n by FINSEQ_2:111;
reconsider rv = v as Element of REAL n by FINSEQ_2:111;
per cases ( k + 1 < j or k + 1 >= j ) ;
suppose A13: k + 1 < j ; :: thesis: S1[k + 1]
then A14: k + 1 < len F by A7, XXREAL_0:2;
A15: 1 <= k + 1 by NAT_1:11;
k < k + 1 by XREAL_1:31;
then A16: |(rv0,fk)| = 0 by A10, A13, Th45, XXREAL_0:2;
A17: |(rv0,(fk + rv))| = |(rv0,fk)| + |(rv0,rv)| by EUCLID_4:33;
k + 1 in Seg (len F) by A14, A15, FINSEQ_1:3;
then A18: k + 1 in dom F by FINSEQ_1:def 3;
then A19: F /. (k + 1) = F . (k + 1) by PARTFUN1:def 8;
then A20: F /. (k + 1) in rng F by A18, FUNCT_1:def 5;
A21: v = (l . (F /. (k + 1))) * (F /. (k + 1)) by A6, A18, RLVECT_2:def 9;
reconsider fk1 = F /. (k + 1) as Element of REAL n by FINSEQ_2:111;
A22: rv0 <> F /. (k + 1) by A1, A6, A13, A18, A19, FUNCT_1:def 8;
|(rv0,rv)| = (l . (F /. (k + 1))) * |(rv0,fk1)| by A21, EUCLID_4:27
.= (l . (F /. (k + 1))) * 0 by A1, A2, A20, A22, Def4
.= 0 ;
then (Euclid_scalar n) . v0,((f . k) + v) = 0 by A16, A17, Th45;
hence S1[k + 1] by A4, A11; :: thesis: verum
end;
suppose k + 1 >= j ; :: thesis: S1[k + 1]
hence S1[k + 1] ; :: thesis: verum
end;
end;
end;
end;
end;
hence S1[k + 1] ; :: thesis: verum
end;
A24: for i being Element of NAT holds S1[i] from NAT_1:sch 1(A8, A9);
A25: for i being Nat st i < j holds
(Euclid_scalar n) . v0,(f . i) = 0
proof
let i be Nat; :: thesis: ( i < j implies (Euclid_scalar n) . v0,(f . i) = 0 )
assume A26: i < j ; :: thesis: (Euclid_scalar n) . v0,(f . i) = 0
reconsider i0 = i as Element of NAT by ORDINAL1:def 13;
(Euclid_scalar n) . v0,(f . i0) = 0 by A26, A24;
hence (Euclid_scalar n) . v0,(f . i) = 0 ; :: thesis: verum
end;
defpred S2[ Nat] means ( $1 >= j & $1 <= len F implies (Euclid_scalar n) . v0,(f . $1) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0) );
A27: S2[ 0 ] by A1, A3, FINSEQ_1:3;
A28: for k being Element of NAT st S2[k] holds
S2[k + 1]
proof
let k be Element of NAT ; :: thesis: ( S2[k] implies S2[k + 1] )
assume A29: S2[k] ; :: thesis: S2[k + 1]
per cases ( k + 1 < j or k + 1 >= j ) ;
suppose k + 1 < j ; :: thesis: S2[k + 1]
hence S2[k + 1] ; :: thesis: verum
end;
suppose A30: k + 1 >= j ; :: thesis: S2[k + 1]
per cases ( k + 1 > j or k + 1 = j ) by A30, XXREAL_0:1;
suppose A31: k + 1 > j ; :: thesis: S2[k + 1]
per cases ( k + 1 <= len F2 or k + 1 > len F2 ) ;
suppose A32: k + 1 <= len F2 ; :: thesis: S2[k + 1]
k < k + 1 by XREAL_1:31;
then A33: k < len F2 by A32, XXREAL_0:2;
1 <= k + 1 by NAT_1:11;
then A34: k + 1 in Seg (len F2) by A32, FINSEQ_1:3;
then k + 1 in dom F2 by FINSEQ_1:def 3;
then F2 . (k + 1) in rng F2 by FUNCT_1:def 5;
then reconsider v = F2 . (k + 1) as Element of (RealVectSpace (Seg n)) ;
reconsider fk = f . k as Element of REAL n by FINSEQ_2:111;
reconsider rv = v as Element of REAL n by FINSEQ_2:111;
A35: |(rv0,fk)| = (Euclid_scalar n) . v0,((l . (F /. j)) * v0) by A29, A31, A33, Th45, NAT_1:13, RLVECT_2:def 9;
A36: |(rv0,(fk + rv))| = |(rv0,fk)| + |(rv0,rv)| by EUCLID_4:33;
A37: k + 1 in dom F by A34, A5, FINSEQ_1:def 3;
then A38: F /. (k + 1) = F . (k + 1) by PARTFUN1:def 8;
then A39: F /. (k + 1) in rng F by A37, FUNCT_1:def 5;
A40: v = (l . (F /. (k + 1))) * (F /. (k + 1)) by A6, A37, RLVECT_2:def 9;
reconsider fk1 = F /. (k + 1) as Element of REAL n by FINSEQ_2:111;
A41: rv0 <> F /. (k + 1) by A1, A6, A31, A37, A38, FUNCT_1:def 8;
|(rv0,rv)| = (l . (F /. (k + 1))) * |(rv0,fk1)| by A40, EUCLID_4:27
.= (l . (F /. (k + 1))) * 0 by A1, A2, A39, A41, Def4
.= 0 ;
then (Euclid_scalar n) . v0,((f . k) + v) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0) by A35, A36, Th45;
hence S2[k + 1] by A4, A33; :: thesis: verum
end;
suppose k + 1 > len F2 ; :: thesis: S2[k + 1]
end;
end;
end;
suppose A42: k + 1 = j ; :: thesis: S2[k + 1]
k < k + 1 by XREAL_1:31;
then A43: k < len F2 by A5, A7, A42, XXREAL_0:2;
F2 . (k + 1) in rng F2 by A1, A42, FUNCT_1:def 5;
then reconsider v = F2 . (k + 1) as Element of (RealVectSpace (Seg n)) ;
reconsider fk = f . k as Element of REAL n by FINSEQ_2:111;
reconsider rv = v as Element of REAL n by FINSEQ_2:111;
(Euclid_scalar n) . v0,(f . k) = 0 by A25, A42, XREAL_1:31;
then A44: |(rv0,fk)| = 0 by Th45;
A45: |(rv0,(fk + rv))| = |(rv0,fk)| + |(rv0,rv)| by EUCLID_4:33;
A46: k + 1 in dom F by A1, A3, A5, A42, FINSEQ_1:def 3;
A47: v = (l . (F /. (k + 1))) * (F /. (k + 1)) by A1, A42, RLVECT_2:def 9;
reconsider fk1 = F /. (k + 1) as Element of REAL n by FINSEQ_2:111;
|(rv0,rv)| = |(rv0,((l . (F /. j)) * rv0))| by A47, A1, A42, A46, PARTFUN1:def 8
.= (Euclid_scalar n) . v0,((l . (F /. j)) * v0) by Th45 ;
then (Euclid_scalar n) . v0,((f . k) + v) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0) by A44, A45, Th45;
hence S2[k + 1] by A4, A43; :: thesis: verum
end;
end;
end;
end;
end;
A48: for i being Element of NAT holds S2[i] from NAT_1:sch 1(A27, A28);
for i being Nat st i >= j & i <= len F holds
(Euclid_scalar n) . v0,(f . i) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0)
proof
let i be Nat; :: thesis: ( i >= j & i <= len F implies (Euclid_scalar n) . v0,(f . i) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0) )
assume A49: ( i >= j & i <= len F ) ; :: thesis: (Euclid_scalar n) . v0,(f . i) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0)
reconsider i0 = i as Element of NAT by ORDINAL1:def 13;
(Euclid_scalar n) . v0,(f . i0) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0) by A49, A48;
hence (Euclid_scalar n) . v0,(f . i) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0) ; :: thesis: verum
end;
hence (Euclid_scalar n) . v0,(Sum (l (#) F)) = (Euclid_scalar n) . v0,((l . (F /. j)) * v0) by A4, A5, A7; :: thesis: verum